Patent GB-897756-A (GB)
Title: Apparatus for providing a stabilised elevated platform
IPC: B64C39/02
Filed: 1958-07-15
Abstract: 897,756. Tethered flying apparatus. ZBOROWSKI, H. P. G. A. R. VON. July 15, 1958 [July 16, 1957], No. 22572/58. Class 4. [Also in Groups XXXI, XXXV and XL(c)] A stable elevated platform is mounted on an elevated body comprising a cowling in which are one or more airscrews and driving means therefor, connected to a powered vehicle at ground or sea level by a mooring device, the body having means operable to produce . a transverse force in a direction opposed to and in magnitude dependent on any transverse displacement of the body, so as at least partially to correct such displacement. In Fig. 1, the body comprises a cowling 1 containing contra-rotating propellers 2a, 2b, driven by an electric motor 3. The body is connected by gimbal rings 22 and a downwardly extending yoke 100 to a cable 6 wound on a drum 7 on a vehicle 8 having power plant 9. The power plant can be connected by clutches either to drive the vehicle, or to wind in or pay out the cable on drum 7, or to drive an electric generator supplying the motor 3 through conductors in the cable. The vehicle also has a cable brake, and means for monitoring any signals from apparatus on the elevated platform. Such apparatus may be a television camera, or radio or television transmission, reception, or relay devices. The platform may be used for observation for artillery. To stabilize the platform, when elevated, against transverse movement, e.g. in winds, a radio, infra red, or light beam is directed upwardly from an emitter f1 on the vehicle, and a receiver f2 is mounted on the body or a reflector is mounted on the body and a receiver on the vehicle, so that such transverse movements can be detected. Alternatively, the body may carry a transmitter, and the vehicle a receiver. Signals representing such movements are used to set up a returning force, for example, by operating surfaces 21, Fig. 16, spaced round the lower edge of cowling 1, to deflect the airstream issuing from the cowling. Such surfaces may instead be mounted on the cowling by brackets, or replaced by retractable spoilers, Figs. 9-12 (not shown). A reference system in the body for determining which surfaces or spoilers require to be operated is set up by gyroscopes. In Fig. 3a, the yoke 100 carries two surfaces S (one shown) to orientate the cowling relatively to the wind, and a horizontal component of thrust from the airstream issuing from the cowling is derived by tilting the cowling by an hydraulic jack Ve connected between the cowling and yoke 100. The cowling may have radial fins at its lower edge. To stabilize the cowling against rotation about a vertical axis, it is connected to the cable 6 by a low friction bearing, and a plane polarized beam of light 37, seen in plan in Fig. 8, is directed upwardly and received by two photocells 36a, 36b, on the cowling, having polarized filters arranged at 90 degrees to each other, each being normally at 45 degrees to the plane of polarization of beam 37. Rotation of the cowling from the orientation, as in Fig. 8, increases output of one photocell and decreases that of the other, and this is used to operate surfaces 32 in the propeller downwash to set up a restoring torque. In Fig. 14, the cable 6 is connected through a yoke and gimbal rings 46 to the driving motor 3, the motor and propeller acting as a gyroscope to stabilize the platform 44 which is mounted on an upward extension of the propeller drive shaft by a bearing 44a, and which is prevented from rotation by a scissors linkage 45. Alternatively, the platform may be stabilized by being connected through springs and dashpots to an inertia ring mounted on the propeller drive shaft by gimbal rings.